ML20070K247
| ML20070K247 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 03/05/1991 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20070K197 | List: |
| References | |
| NUDOCS 9103180365 | |
| Download: ML20070K247 (4) | |
Text
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NUCLEAR REGULATORY COMMISSION 5
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pfETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDHENT NO. 84 TO FACILITY OPERATING LICENSE NPF-35 AND AMENDMENT NO. 78 TO FACILITY OPERATlhG LICENSE NPF-52 DUKE POWER COMPANY, ET AL.
CATAWBA NUCLEAR STATION, UNITS 1 AND 2 DOCKET N05. 50 413 AND 50-414
1.0 INTRODUCTION
By letter dated December 19, 1990, Duke Power Company, et al. (the licensee) proposed changes to the Catawba Nuclear Station, Units 1 and 2 Technical Specification (TS) 4.4.5 and associated Bases. The proposed change would revise the surveillance requirements of Technical Specifications 3/4.4.5, " Steam Generators," to permit the option of using the Babcock & Wilcox (B&W) kinetic sleeving process for steam generator tube repair.
The requested Technical Specifications change will allow the use of B&W sleeves for steam generator tute repair as alternative to plugging degraded tubes.
The change references B&W topical report BAW-2045P, " Recirculating Steam Generator Kinetic Sleeve Qualification for 3/4 Inch OD Tubes," in Technical Specifica-tiens Section 4.4.5.4.a.6.
The topical report was submitted to the NRC by a letter dated June 9, 1988, and a supplement to the original submittal was made c' December 12, 1988, which contained answers to the NRC request for additional inforution. The staff approved the topical report as being suitable for referent.$r.g in a letter to James H. Taylor of B&W from James E. Richardson dated January 4, 1990.
The purpose of a sleeve is to repair a degraded steam generator tube in order to maintain the function and integrity of the tube.
The sleeve functions in essentially the same manner as the original tube.
B&W topical report BAW-2045P describes in detail the analytical rnethods used for design and qualification of the B&W sleeve. The topical report lists the specifications (mainly ASME Boiler and Pres are Yessel code requirements) used in design, procurement and qualification of the sleeve.
It also summarizes the transients used to establish sleeve leading.
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2 2.0 E1ALVATION BAW-2045P ccntains the results of the sleeve design verification which included analysis and confirmatory testing to demonstrate the acceptebility of the steam generator sleeving technique for defective tubes.
The design and operating conditions specified for the sleeve bound the Catawba steam generator design conditions.
The sleeve design described in BAW-204SP is qualified for two lengths, 11 inches and 17 and 1/2 inches.
The lower end of each sleeve is located approximately 16 inches from the primary face of the tubesheet.
The shorter sleeve mr. A utilized in all the steam generator tubes (including the periphe *
- ubes which typically do not permit the introduction of siteves due to the close proximity of the bowl in that area).
The longer sleeve extends further into the tube past the flow distributien baffle.
The sleeve material is thermally treated Alloy 690 Inconel with a specified minimum wall thickness of 0.039 inches.
The required minimum thickness is 0.027 inches based on primary side design pressure. This material has been demonstrated to be resistant to corrosion phenomenon as detailed in BAW-2045P.
The upper sleeve / tube joint is produced by a kinetic weld / expansion which is subsequently stress relieved.
The joint is qualified as both a strength and seal weld. The lower Joint may consist of either a kinetic weld in the tubesheet or a mechanically scaled joint produced by rolling the sleeve in the tubesheet. The lower joint is qualified for applicable loads without taking credit for the original strength of the tube rolled into the tubesheet.
Therefore, the structural integrity of the tube is maintained by the sleeving process.
The adequacy of the sleeve to withstand cyclic loadings was demonstrated using fatigue testing.
Fatigue testing consisted of cyclic vibration, pressure, thermal, and axial loading. These tests were performed to demonstrate the structural adequacy of the installed sleeve.
In all cases, the results of the tests indicated that the sleeve conformed to the design requirements of the steam generators.
Based on Regulatory Guide 1.121 guidelines for tube degradation limits, a plugging lim't of 40% of the original sleeve well has been estabb shed.
Eddy current techniques are available to perfurm necessary sleeve / tube inspections for defect detection and to verify proper installation of the sleeve.
The Licensee has stated that available techniques are capable of providing 20%
defect sensitivity in the required areas of the tube / sleeve pressure boundary.
A proprietary method is described in the topical report with supporting validation data that demonstrates the inspectability of the sleeve and underlying tube. The Licensee has provided a ccmmitment to validate the adequacy of any system that is used for periccic inservice inspections as well as a commitment to upgrade testing methods as better methods are developed and validated for commercial use.
1 l
11 The following conclusions are based on the staffs previous review and approval of BAW 2045P as revised to include the changes described in the letter dated December 12, 1988, from James H. Taylor, B&W, to Lawrence C. Shao, NRC (hhC Accession Number 8901040142).
The staff has concluded that there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner and the issuance of this cmendment is acceptable.
3.0 EhVIRONMENTAL CONSIDERATION These-amendments invohe changes to requirements with respect to the use or installation of components located in the restricted area as defined in 10 CFR Part 20, and changes in surveillance requirements.
The staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Commission has previously issues a proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on such finding.
Accordingly, the arrendments meet the eligibilitycriteriaforcategoricalexclusionsetforthin10CFR51.22(c)(9) and51.22(c)(10). Pursuant to 10 CFR 51.22(b), no environmental assessment need be prepared in connection with the issuance of these amendments.
4.0 CONCLUSION
The Commission's proposed determinaticn that the amendments involve no significant hazards consideration was published in the Federal Register (56 FR 2053) on January 18, 1991.
The Connission consulted with the State of South Carolina. ho public comments were received, and the State of South Carolina did not have any corma:nts.
We have concluded, based on the considerations discussed above, that (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be condected in compliance with the Commission's regulations, and the issuance of these amendnients will ret be inimical to the common defense and security or the health and safety of the public.
Principal Contributor:
H. Conrad, EMCB Dated March 4, 1991